The diagnosis of the syndromes in asymptomatic patients can be made by genetic screening. We are currently supervising one of the largest documented families in Germany with genetically determined SDHD gene mutation. Penetrance data would suggest that if screening commenced at 10 years of age, disease would be detected in approximately 96% of patients with an SDHB mutation and in all SDHD mutation carriers. Having confirmed the diagnosis, it is important to localise the tumours and reveal the tumour extent preoperatively. We performed 18F-DOPA PET CT as a new non-invasive and reliable screening method to detect tumors in so far symptomatic gene carriers and enable subsequent surgical therapy.

Results: Our paraganglioma-pheochromocytoma tumor syndrome family has a documented family tree of 35 persons in 5 generations. 6 persons in two generations have genetically determined SDHD mutations. So far we performed 18F-DOPA PET CT in 3 family members and revealed 8 tumors, partially not detected in CT. Two of these persons underwent successful neurosurgical treatment. The third family member is under supervision. Consecutive screening of other family members is planned.

Conclusions: The 18F-DOPA PET CT scan of three so far asymptomatic family members with genetic mutation of SDHD gene revealed paraaortic, adrenal and cervical mass lesions, partially not detected in CT. This enabled early surgical intervention and presumably improved the prognosis of these patients. We therefore assume that PET CT scan is a low-risk and meaningful diagnostic tool for rare genetic disorders such as Pheochromocytoma-paraganglioma inherited tumor syndrome for early detection of mass lesions and consecutively prompt intervention.